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Subject: TWL: RE: Hot water heater story (long)
From: Keith Pleas (keithp@XXX.XXX)
Date: Wed May 01 2002 - 13:25:07 EDT
>>>>2. Many heaters are connected via pipe or wire-wrapped tubing. Both
of
these can establish an electrical connection and increase corrosion
dramatically (and decrease life).<<<<
>>Presumably these are used in anticipation of relatively high
pressures. What should be used instead?
My boat happens to use rigid plastic pipe, but he also mentioned a new
flexible high pressure water hose that was not wire-wrapped.
>>>>4. Tanks without an upstream accumulator - which must be downstream
of
any checkvalve before the heater - can result in very high pressures in
the
tank, which most tanks cannot typically withstand.<<<<
>>I don't quite understand this... Why would the absence of an
accumulator produce higher pressures?
When the water in the tank is heated, it expands. And it needs a place
to expand into, ideally an accumulator tank. The problem arises if a
check valve is fitted upstream of the heater _between_ the heater and
the accumulator. This creates a "hard" system with no give.
>>>>5. The internal fittings to the tank for inlet and outlet typically
have
directed hoses on them, which means that the tank should be mounted per
the
manufacturer's recommendations to be effective.<<<<
>>What is a directed hose? Is it one with one-way valves in it?
The inlet and outlet fittings to the tank have (at least for the ones I
saw) 8" hoses _inside_. These hoses are angled by design. At least on
the Torrid tanks, it warns on the front to not turn the fittings (though
people might think this refers to whatever is _attached_ to the
fitting). A related issue is that if these aren't aligned properly you
will end up with a large air bubble in the tank itself. Not inherently
harmful, but it reduces your capacity.
>>>>6. The use of a watermaker will dramatically shorten a water
heater's
life, though filtering the water before it enters the watermaker can
help.<<<<
>>Eeek! You can't just leave us all hanging here! HOW does the use of a
water maker dramatically shorten a water heater's life?
Dunno. <g> A couple of people have e-mailed me privately on this, so
it's clearly of interest. I'll have to ask tomorrow...
>>Regards, Robert Bryett
Sydney, Australia
Funny, I was just down there last week! Did a conference at the Westin
downtown including an all-day seminar on Anzac Day. Talk about poor
planning! Anyway, I loved your Maritime Museum.
Keith
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